Mobile ad-hoc networks have become increasingly important in areas where deployment of communication infrastructure is difficult. A mobile ad-hoc network (MANET) is formed by multiple moving nodes equipped with wireless transceivers. The mobile nodes communicate with each other through multi-hop wireless links. Each node equipped with a wireless transmission can transmit and receive information.
One type of MANET is a vehicular ad-hoc network (VANET) that refers to a mobile ad-hoc network designed to provide communications among nearby vehicles and between vehicles and nearby fixed equipment. In a typical roadway, there are vehicles that are equipped with a wireless communication device and others that are not. Road conditions vary in different environments such as a metropolitan areas verses a rural environments as well as for different types of roads such as highways, interstates, tunnels, local roads and bridges.
This variation in local environmental conditions affects the performance of a wireless communications device and ultimately the ad-hoc network that includes multiple communication devices. In a VANET the variance in local environmental conditions and the change in performance of each wireless communication device due to the variance of the local environmental conditions are accentuated since each vehicle is moving at high speeds. Key performance requirements include low latency (on the order of 100 milli-seconds) and sustained throughput (or equivalently, the percentage of neighboring vehicles that successfully receive warning messages) in order to support various applications such as collision avoidance. For example, information that is necessary for setting up safety communications must be exchanged in real-time, and vehicles in the groups must configure themselves in real-time so that safety communication can take place. The high mobility of uncoordinated vehicles implies frequent change of neighbors or vehicle groups, and poses difficulties of using support-servers (for mobility, address, name, media session) within vehicle groups. These key differences make existing mobile ad-hoc networking technologies (such as tactical ad-hoc networking) not directly applicable to vehicle groups.
Therefore, a wireless communication device must be able to adjust its performance or operating parameters based upon the change in local environmental conditions.